Notes on the Bible, by Albert Barnes, [1834], at sacred-texts.com
Although in some degree baffled in his own pursuit of wisdom, Solomon yet regards wisdom as the nearest approach to "that good for man" which he is seeking; and presses here, as a part of that wisdom, a spirit of obedience Ecc 8:1-5. In the face of the incomprehensible course of external events, he determined to abide in the fear and trust of God Ecc 8:6-14, and to acknowledge the natural incompetence of every man to find out the unsearchable ways of God Ecc 8:15-17.
And who - Rather, and as he who knoweth. The possessor of wisdom excels other people: it imparts serenity to his countenance, and removes the expression of gloom or fierceness (see the marginal reference).
Oath - A reference to the oath of allegiance taken to Solomon at his accession to the throne (the margin of Ch1 29:24).
Stand not ... - i. e., "Do not persist in rebellion."
Feel - literally, know. The meaning is, "He who obeys the commandment (i. e., the word of the king, Ecc 8:4), will not be an accomplice in any act of rebellion; and if he be a wise man he discerns (literally knows) that the king's commandment or action is liable to correction, if it be wrong, in God's time and by God's judgment." Compare Ecc 3:11, Ecc 3:17.
Because, therefore - , Or, as in Ecc 8:7, "for."
The possibility of God's time and judgment being in opposition to a king's purpose or commandment Ecc 8:5, suggests the thought that such discord is a misery (evil, Ecc 6:1) common to man (or, mankind).
When - Or, as in the margin. For the meaning of this verse, compare marginal references.
Neither hath he power - Rather: "and there is no power." Compare Ecc 3:19.
No discharge ... - i. e., "No exemption from the final hour of struggle between life and death."
Wickedness - Though the life of the wicked may be prolonged Ecc 7:15, yet wickedness itself has no inherent power to prolong that life.
To his own hurt - Or, "to the hurt of the subject." The case is still that of an unwise king whose command is obeyed Ecc 8:2 even to the hurt of the wise man who obeys him.
i. e., "I saw wicked (rulers) buried, who came into the world and went from the Holy place (the seat of authority and justice, Deu 19:17; Ch2 19:6), and they were forgotten in the city where they had so ruled to the hurt of their subjects: this - their death and oblivion - shews their lot also to be vanity." Others interpret the verse: "I have seen wicked men buried; and (others) came into the world, and from the Holy place they went out of the world, and were forgotten in the city where they had done rightly" (compare Kg2 7:9).
His days be prolonged - i. e., in his wickedness Ecc 8:8.
"I" is emphatic, as if to mark the opposition to the "sons of men" Ecc 8:11.
Which is done upon the earth - The instance of vanity, to which these words are applied, is the seeming inequality of God's justice; but if they are considered in connection with the profession of personal faith in God's absolute justice Ecc 8:12, the conclusion is irresistible, that, whatever reason the Preacher had for reserve in declaring his belief, he certainly looked forward to final judgment in a future state of existence (compare Ecc 3:17; Ecc 12:14).
Mirth - Better, Gladness, or "joy" (as in Ecc 2:10). The Hebrew word is applied not only to the pleasures arising from the physical senses, but also frequently to religious joy. The sentiment of this verse is a frequent conclusion of the writer's personal experience (compare marginal references), and is unfairly charged with Epicureanism. The Preacher is careful to set forth pleasure as a gift from God, to be earned by labor, and received with thankfulness to the Giver, and to be accounted for to Him. His estimate of the pleasures of the senses is recorded in Ecc 7:2-6.
These verses supplement Ecc 8:15 with the reflection that the man who goes beyond that limited sphere within which he can labor and be contented, and investigates the whole work of God, will find that his finite intelligence cannot grasp it.
Business - Or, "travail" Ecc 1:13; Ecc 3:10. The sleeplessness noted probably refers to the writer himself.